Abstract: A multi-screw extruder consists of contra-rotating screws (20) inserted in a housing, whose flights (1) form intermeshing crests (2) and roots (3), and which have at least two axial sections (21, 22, 23) of flights each differing in number and pitch. To improve the manufacturing conditions, and to achieve uniform wear conditions over the screw length, adjacent axial sections (21, 22, 23) of a screw (20) verge into each other within an axial transition zone (24) free from annular grooves, where all roots (3) extend through the transition zone (24) while making turns (.alpha.) and forming ramifications or combinations (V), and at least one of the crests (2) begins or ends in the transition zone (24).

Abstract: A multichannel wave plasticating screw having a feed section, barrier melting section, and metering section wherein solid material is transitioned from the trailing side of the primary flight to the push side of the primary flight at the terminal end of the barrier melting section. The solids transition is accomplished by interchanging, or "reversing" the diameter and width of the primary and secondary flights at the terminal end of the transition section. Alternatively, the barrier flight includes a short section of increased pitch at the terminal end of the barrier melt section which abruptly narrows the solids channel and thereby forces solid material over the barrier flight into the melt channel and on the pushing side of the primary flight. Transferring solid material from the trailing side to the push side of the primary flight increases the shear and pressure applied thereto and more quickly and efficiently melts solids.

Abstract: A multiple-screw extruder in which paired co-rating screws, or segments thereof, contain unequal numbers of flights; and a screw for use in such extruder.

Abstract: A screw for an in-line screw type thermosetting resin injection molding machine comprises a resin kneading portion in a front end portion of a full-flighted screw. In the resin kneading portion, a groove having a crest portion and a trough portion formed spirally in a circumferential direction, and a step portion. A difference between a radial dimension of the step portion and an outermost radial dimension of the crest portion is 10% to 60% of a difference between the outermost radial dimension of the crest portion and an innermost radial dimension of the trough portion. The axial length of the resin kneading portion is 0.5 to 2 times as long as the outer diameter of the full-flighted screw, or 0.5 to 2 times as long as the pitch of the full-flighted screw.

Abstract: An extruder for plasticating and extruding an extrudate, and an extrusion screw used with the extruder form the subject of this invention. The extruder screw includes an elongated root body and a thread portion helically wound about the root body and extending along the length. The screw having a low compression ratio, flight with a reduced helical angle, and a conical, tapered front end section where at least one-half flight of the thread has a pitch associated therewith which is different from the pitch of the remainder of the thread and where the diameter is less than the diameter of the remainder of the root body.

Abstract: An extrusion apparatus for processing, mixing and extruding thermoplastic and rubber materials includes a feed hopper feeding two barrier type extruders. Extrusion rotors include diagonal grooves with a barrier that has a restrictive clearance or gap relative to the extruder barrel bore. Fine material can pass through this gap, but larger material is led to a downstream end of the grooves. An abrasive barrel surface opposite the downstream end of the grooves grinds this larger material until it can pass or lead off through the smaller gap. Stationary knives located downstream of the abrasive section cut the exiting material into flakes. The barrel and barrier sections are conical and the size of the gap can be changed by relative movement between the barrel and the barriers. The extruders can operate adiabatically so that there is no change in extrusion temperature with speed and the volume of process flow.

Abstract: An apparatus for shearing and straining polymeric process material, such a scrap tires includes a rotor and barrel. Large material pieces are feed into a hopper and the material is warmed, pressurized and transported to a rotor--barrel transfer section to initially chop the material to reduce its size. The material then passes to a rotor barrier or refining section where the material must pass over wide top barriers that extend across extrusion grooves. The barriers included multiple ridges and the barrier to bore clearance is progressively reduced as the material passes downstream. Ramp like grooves, where rejected material can be worked further, precede the barrier ridges. A rotor to barrel transfer section, having a conical barrel that can be longitudinally shifted, follows the wide top barriers, so the size to the discharged material can be regulated.

Abstract: A method of eliminating gel contained in polymer, by efficiently plasticizing and melting the polymer supplied into a barrel with the stress in a rotor reduced, and next kneading the polymer with a rise in temperature of the polymer suppressed and a residence time of the polymer in the barrel increased. A continuous kneader for realizing this method is also provided. The gel eliminating method includes the first step of plasticizing and melting the polymer by using a first rotor having a given number of wings; and the second step of kneading the polymer after the first step by using a second rotor having a given number of wings fewer than the number of wings of the first rotor, so as to suppress a rise in temperature of the polymer and increase the volume of a kneading chamber to thereby increase a time period of residence of the polymer in the kneading chamber. The continuous kneader includes a rotor having the first rotor and the second rotor.

Abstract: A process and an apparatus for recycling resin scrap including a thermosetting resin paint film and a thermoplastic resin substrate as its major components, wherein the resin scrap is supplied into a passage of a cylinder, melted, and delivered by screw arrays from an upstream side to a downstream side of the passage of the cylinder, and hydrolyzed by a hydrolyzing agent while forming a highly packed region with a resistor. The resistor restricts the resin scrap to flow from the upstream side to the downstream side in a short period of time, and forms the highly packed region where a contact efficiency is enhanced between the resin scrap and the hydrolyzing agent.

Abstract: The present invention provides a dough transport device having an improved dough pump, an improved manifold for dividing dough, and a rotational cutter for cutting dough into pieces of uniform shape and size. The auger dough pump operates using a auger which is tapered to provide for more efficient control over the transport of the dough. Further, the rotational cutter cooperates with a curved face of each outlet nozzle in the manifold to provide for a curved dough shape upon initial cutting of the extruded dough.

Abstract: A mixer for delaminating, deagglomerating, mixing, and extruding a mixture of powder and liquid, which contains a mixing chamber, a variable speed rotating shaft disposed within the chamber, a multiplicity of stators extending from the interior wall of the chamber towards the shaft, and a multiplicity of differently configured auger blades connected to the shaft. The device contains a first, second, and third set of auger blades, each of which is connected to the shaft. The first set of augur blades has a pitch which is at least twice as great as the pitch of each of the second and third set of augur blades, and it also has a smaller face area.

Abstract: An extruder device includes a rotor rotatably received in a housing and a tube secured to the rotor and having a helical screw formed in the outer portion. A screw member is engaged in the bore of the rotor and secured in the tube and rotated in concert with the tube and the rotor. The material to be extruded is supplied onto the tube and moved by the helical screw and then by the screw member. The helical screw includes a pitch greater than that of the screw member for allowing the helical screw of the tube to squeeze the material.

Abstract: The present invention comprises an extrusion arrangement for the controlled compounding and mixing of a plurality of time, pressure and condition sensitive substances in a single screw plastic extrusion machine, having a main support shaft connected to the downstream end of a single screw plastic extrusion machine, the support shaft enclosed within a barrel shaped housing, at least one stator and one rotor being disposed about the support shaft within the barrel shaped housing, and at least one satellite extrusion feeder arranged to supply an additive to the barrel shaped enclosure through an introduction port, the introduction port arranged at a location radially adjacent a rotor on its support shaft.

Abstract: An apparatus for solid state shear extrusion pulverization of a polymeric material comprising an elongated hollow barrel having a feed zone, a heating zone adjacent to the feed zone, a powder formation zone adjacent to the heating zone, and a powder discharge zone adjacent to the powder formation zone. At least one screw is housed within the elongated hollow barrel. A hopper is provided for feeding the polymeric material into the feed zone of the elongated hollow barrel. Barrel heaters and coolers are provided for heating the polymeric material to a temperature less than its decomposition temperature in the heating zone and for maintaining the polymeric material below its melting point in the powder formation zone. The screw comprises a high shear screw section for applying normal and shear forces within the powder formation zone to form a powder of the solid state polymeric material.

Abstract: A mixing apparatus suitable for mixing and conveying solid, particulate, polymeric materials, comprising a barrel that can be heated and cooled, at least two co-rotatable, self-wiping extruder screws located within the bore of the barrel, the screws being connected through a laterally flexible coupling to a dirve means which can reverse the direction of rotation of the screws upon the occurrence of a predetermined event. The apparatus also comprises a closeable feed port and a closeable discharge port, both of which can be made gas-tight, the shafts of the screws being provided with seals capable of withstanding elevated gas pressures inside the barrel.

Abstract: An extrusion screw (13) for an extruder (11) includes a screw shaft (24 ) which is rotatably arranged in a cylinder barrel (12). A main flight (25) and an auxiliary flight (26) are helically provided on the outer peripheral surface of the screw shaft (24). The trailing ends (25a, 26a) of these flights (25, 26) are spaced from each other by a half turn in the circumferential direction (A) of the screw shaft (24). A main flight groove (32) is formed between the front wall surface (27) of the main flight (25) and the rear wall surface (29) of the auxiliary flight (26). An auxiliary flight groove (31) is formed between the front wall surface (28) of the auxiliary flight (26) and the rear wall surface (30) of the main flight (25) to have a second cross-sectional area. The cross-sectional area of the auxiliary flight groove (31) decreases in a direction from the leading end (26b) to the trailing end (26a) of the auxiliary flight (26).

Abstract: Improved short length extrusion cooking devices (10) are provided which can achieve product throughput and quality characteristics of conventional long-barrel extruders. The short length extruders (10) of the invention include a relatively short barrel (14) having an inlet (18) and an endmost extrusion die (20). An elongated, helically flighted axially, rotatable screw assembly (22) is positioned within the barrel (14) and is coupled to motive means (39, 39a) for rotation of the assembly (22) at a speed of at least about 500 rpm. The device (10) includes an internal, apertured flow-restricting device (60, 110) which defines a mid-barrel choke point for the material being processed. Preferably, the barrel (14) has an internal bore of generally frustoconical configuration with an effective length to maximum diameter ratio (L/D) of at least about 6.

Abstract: An extruder screw having a plurality of plasticating sections sufficient for plasticating polymeric materials of different bulk density.

Abstract: An apparatus for degassing thermoplastic synthetic plastics material has a first screw section (11) for the intake of the material to be treated. The plasticized synthetic plastics material flows from the housing (10) of this screw section (11) through a connection channel (15) to a filter (16) and from there through an inflow opening (17) into the housing (18) of a second screw section (19) which conveys the material to an outlet (21). Between the two coaxial screw sections (11, 19), a sealing section (26) is disposed which avoids a by-pass of the filter (16). A baffle member (28) is disposed in front of the inflow opening (17) which forces the synthetic plastics material stream into a hose-formed shape. The baffle member (28) is displaceable with respect to the inflow opening (17) in axial direction and has a cross section which tapers towards the second screw section (19).

Abstract: An extruder screw for use in the barrel of a plastic materials extruder is formed with a melt section which includes a melt flighting and a compaction channel and which also includes a barrier flight in which only smooth transitions are formed to prevent pressure surges or disruptions. The barrier flight rises radially outwardly of a forward wall of the melt channel, and defines a clearance space with the adjacent wall of the barrel which varies from a maximum at the beginning of the barrier flight to a minimum at the end of the barrier flight. The varying clearance between the barrier flight and the barrel wall approximates the change in viscosity of molten plastic material flowing over the barrier flight from the solids channel into the melt channel, so that a relatively constant shear energy input is applied to the molten plastic material flowing over the barrier flight.

Abstract: In a screw element for the conditioning and/or processing of plastics or elastomers in a screw-type extruding machine having screw shafts drivable to rotate in the same direction and at least one pair of meshing screw elements, each screw element having a land of which the enveloping curve extends radially at a constant distance away from the respective shaft and, in the longitudinal direction, is of linear extension in parallel to the longitudinal axis of the shaft, a radially external screw land section near the housing running parallel to the inside wall of the housing with little play relative to the latter, for the purpose of moderate recirculation without stress points accompanied by strong axial and transverse mixing in a defined volume, it is provided that the enveloping curve encloses a blade land of reduced cross-sectional area referred to the enveloping curve, in that starting from the one axial end of the screw element and the first, in the circumferential direction external, end of the section, n

Abstract: The invention relates to a multiscrew, continuous mixing machine for plasticizable compounds with two screws, which rotate in a housing and which penetrate the cylindrical part of the housing that envelops the screw concerned and exhibit feed and metering sections and inbetween at least one homogenizing section and a mixing section, whereby the feed and metering sections are formed by intermeshing conveying screws, which rotate in the same direction and are arranged in the mixing elements, which are opposite the homogenizing and mixing sections and whose edges travel past each other with little clearance while rotating, whereby to form a chamber extending above the mixing elements, the edges maintain a distance from the part of the housing enveloping said edges that is significantly greater than the clearance.

Abstract: A method and mixer for mixing peat and sludge into a homogenous mass, in which method the peat and sludge is mixed by pressurizing the pre-mixed mass for some time, when the sludge is absorbed by and bound in the peat. The mixer in accordance with the invention includes a silo (1) and a screw conveyor (4) located beneath it, from which the mass is squeezed out through a nozzle (10).

Abstract: A melt-sealing device for extruders for thermoplastic polymers or rubber for sealing off the gear unit side against high-melt pressure, in which sealing is effected by the configuration of the extruder screw which includes an intake section, a compression section having a channel depth that decreases in the conveying direction, a metering section with a constant screw channel depth, a smooth annular melt channel section, and a blister element with an annular gap for the sealing melt.

Abstract: A screw for a double-shaft extruding device having a shaft and a spiral flight provided at an outer periphery of the shaft. A height of the flight from an axis of the shaft is substantially constant. An angle of torsion of a spiral of the flight becomes smaller toward a shaft distal end. A cross-sectional area of extrusion formed by the shaft and the flight continuously increases from the shaft distal end to a shaft proximal end. Material can be smoothly discharged and completely extruded.

Abstract: A method of extruding a substantially uniform polymer composition made up of polyvinylchloride, a stabilizing additive composition and at least one of two additional constituents, one of which is a mineral filler and the other of which is a normally liquid plasticizer for the polyvinylchloride; the method is achieved while avoiding use of compounded PVC as a starting material and includes the steps of: (I) providing an extruder; (II) operating the rotors of the extruder for essentially synchronous rotation in a common direction while maintaining in the extruder cavity a temperature sufficient to plasticize the polyvinylchloride; (III) feeding particulate polyvinylchloride and the additive composition without substantial premixing of the polyvinylchloride and the additive composition into the cavity at the first inlet (e.g.

Abstract: An apparatus for extruding material is provided which includes a barrel and a screw. The barrel has an axis and an internal operating surface, the internal operating surface defining a barrel interior and a barrel helical thread portion which includes a plurality of grooves reducing in cross-sectional area from a maximum value to a minimum value in a direction axially opposite to the axial direction of flow of material through the barrel. The screw has an external operating surface and extending into the barrel interior, the external operating surface of the screw forming a screw helical thread portion having at least a first and second groove. Each of the first and second grooves has an upstream end, a downstream end, and a body portion extending between the upstream and downstream ends thereof, the first and second grooves being axially co-incident at at least a transition location and being at least partially axially co-extensive.

Abstract: An apparatus for filtering and extruding plastic scrap consists of an extruder housing having an interior chamber and an extruder worm received and supported for axial rotation in the chamber. The extruder worm includes a centrally located set of return threads which divide the chamber into first and second chamber portions. The housing further includes an intake opening in the first chamber portion for receiving raw material, an exit opening in the second chamber portion for discharging filtered material, and a degassing opening in the second chamber portion for discharging gasses from the chamber. A drive mechanism is provided for rotating the extruder worm. A filter channel connects the first and second chamber portions wherein the plastic material passes from the first chamber portion to the second chamber portion through the channel. The channel has an inlet opening in the first chamber portion and an outlet opening in the second chamber portion.

Abstract: A process and apparatus for pulverization of natural and synthetic polymeric material by heating to a pre-melt or softening temperature below its melting point, cooling and applying high normal and shear stresses sufficient to form fine powder, and fluidizing the powder in a gas stream preventing its agglomeration. The same process and apparatus is suitable for enhancement of reactivity of polymeric and solid monomeric material to form homopolymers, copolymers, and new polymeric materials.

Abstract: In a serial two-stage extruder, the first-stage extruder has a screw including a feed screw section having a length within a range of 5 to 9 the major diameter thereof, a mixing screw section having a hexagonal cross section and a pitch of 1 to 3 times the major diameter thereof, and a metering screw section having a screw groove of an appropriate depth. The second-stage extruder includes an extruding screw and a barrel. The extruding screw has a screw groove of an appropriate depth and a dulmage formed at the tip end of the screw. The dulmage has a plurality of fins cooperating with fins of the barrel. Alteratively, in the second-stage extruder, the dulmage may have a plurality of axially spaced stages of fins. Configurations of the fins in each respective stage are identical but various characteristics of the fins vary from stage to stage. In this case, the barrel does not have fins.

Abstract: A process and apparatus for pulverization of natural and synthetic polymeric material by heating to a pre-melt or softening temperature below its melting point, cooling and applying normal and shear stresses sufficient to form fine powder, and fluidizing the powder in a gas stream preventing its agglomeration. The same process and apparatus is suitable for enhancement of reactivity of polymeric and solid monomeric material to form homopolymers, copolymers, and new polymeric materials.

Abstract: A process and apparatus for pulverization of thermosetting, crosslinked thermoplastic and natural polymeric materials by applying normal and shear stresses by oppositely rotating meshing conical screws sufficient to form fine powder. The process may be conducted at relatively low temperatures, and in the case of many materials, at ambient or near ambient temperature and pressure conditions. The fine powder may be fluidized to aid in its discharge.

Abstract: Convenient access for quick and thorough clean-out and maintenance of an openable mixing chamber and both rotors in two-rotor continuous mixers for plastic materials is advantageously achieved by making each rotor in three separate pieces: a drive journal, a rotor body (also called a "rotor section" or a "rotor") and a driven journal. These three separate pieces of each rotor are axially aligned, with the rotor body being positioned between the drive journal and the driven journal. Each rotor body is disengageably coupled to its respective drive and driven journals. The drive and driven journals are rotatably mounted in bearing assemblies which are separate from the mixing chamber barrel (also called a "mixing chamber housing").

Abstract: A screw-type resin injection apparatus for injection molding which includes a cylinder element having a cylinder chamber for receiving resin therein, and having, at an end portion, a nozzle for injecting the resin. A screw element is arranged within the cylinder chamber in a manner allowing rotation and axial movement. A rotary drive shaft is connected to the screw element telescopically so as to be capable of transmitting a torque. The rotary drive shaft is rotatively driven by a motor. A fluid pressure cylinder unit is arranged laterally of the cylinder element in parallel relation thereto. The fluid pressure cylinder unit is rotatably engaged with the screw element to drive the screw axially. Preferably, the screw element is provided with a mixing screw portion which has a screw groove small in pitch and large in lead angle and an axial groove extending axially.

Abstract: A mixing head for thoroughly mixing and uniformly dispersing a dry filler material within a single liquid or a reactive mix. Dry filler is supplied to the compression chamber of the mixing head. A compression auger is mounted in the compression head is driven by a first drive shaft and compresses the dry filler. The speed of rotation of the compression auger is altered in response to the relative pressure of the dry filler within the compression chamber as measured by a pressure sensor. Air expelled from the compressive dry filler is removed through a port in the compression chamber. The compressed dry filler is conveyed to the mixing chamber of the mixing head. The mixing element is rotatively mounted within the mixing chamber for thoroughly mixing the dry filler with the liquid components. The mixing element is driven by a second drive shaft and can be driven in an opposite direction of rotation from the compression auger.

Abstract: A screw kneader for a plastic material in which a pair of longitudinal screws are rotatably mounted in respective bores for conveying plastic material through the kneader. The screws have spaced portions for advancing the plastic material from an inlet region to an outlet region and between the spaced portions is a section with reversed threads opposing plastic flow to effect mixing of the plastic material. The threads of the intermediate section are provided with openings to permit passage of up to 20% of said plastic material in the direction of advance. Transfer elements with helical threads connect opposite ends of the threads in the intermediate section with the threads of the inlet and outlet regions. The transfer elements of the two screws mutually engage one another to strip plastic material from one another and from the walls of the bores.

Abstract: A plasticizing unit is provided for palsticizing material which is subsequently supplied to an injection molding press. The unit includes a screw disposed in a barrel which has an inlet, an outlet, a reservoir zone portion, and a plasticizing zone portion. The plasticizing zone portion of the barrel and the screw each have a continuous helical groove of opposite hand as the other groove and the grooves transfer material therebetween to effect plasticizing of the material. The reservoir zone portion of the barrel receives a shot volume of material which has been plasticized during passage through the helical grooves of the barrel and the screw. A volume displacement member which is axially movably disposed in a bore of the screw is movable within the reservoir zone portion to selectively control the shot volume of plasticized material received in the reservoir zone portion.

Abstract: A machine for manufacturing thermoplastic polymers including a plurality of coaxial components adjacent to and made integral with one another, the components forming a longitudinal chamber receiving a pair of interacting shafts having portions correspondingly differentiated to provide sections for feeding and premixing the compound, thus forming a single assembly with coaxial components capable for carrying out full processing of the compound from the raw material to extrusion, without discontinuity of sequence.

Abstract: An extruder for poorly miscible extrudates which includes a pin-lined barrel section and a transfer mixing section used together. Restricting pins are arranged in the transfer mixing section in the region of the greatest barrel channel volume and permit universal use of the extruder with respect to the extrudate. The combination of the two mixing systems allows in a surprising way an increase in the material throughput of 60% to 100% with the mixing quality remaining the same and a halving of the drive torque. Due to a constant number of channels of the barrel channels and screw channels, the number of barrel flights and screw flights remains independent of the channel cross-sectional area of barrel and screw. A helical barrel groove in the feed zone of the extruder barrel additionally improves the mixing quality of the extrudate and the output of the extruder.

Abstract: An extrusion apparatus is provided for the mixing and extrusion of thermo-plastic and thermo-setting materials and the pelletizing of thermo-set materials, in which a rotor member is rotatable within a barrel member. The apparatus is articulated into three sections including a barrel entrance section, a forcing section and a metering section. Each section is provided with helical rotor extrusion grooves, and is followed by a circumferential barrier and a rotor to barrel to rotor mixing zone. The circumferential barrier is provided with a clearance, barrier top to barrel bore, designed to pass fluent material and retarding the over-size and less fluent material. The leading edge of the circumferential barrier is provided with multiple dual purpose plows which, direct the fluent material downstream and the over-size and less fluent material upstream for additional working.

Abstract: A mixing section for an extrusion or injection screw has alternating helical wiping and barrier lands which form inlet and outlet channels therebetween, with the barrier lands having a greater helix angle than the wiping lands, creating a conjunction of the adjoining wiping and barrier lands near the input and exit ends of the mixing section. The barrier lands also have notches cut therefrom to promote mixing and throughput. The barrier lands are widened at the conjunction with the wiping lands to form the termination of the downstream end of the inlet channels and the beginning of the upstream end of the outlet channels. Some or all of the channels do not have uniform depths such that the channels gently rise up to the narrowed beginning of the outlet channels and the narrowed ending of the inlet channels, with this tapering avoiding any pocket or hang-up area where melt flow could gather or degrade.

Abstract: An elastomer masterbatch or a compounded productive elastomer stock is made using a twin screw extruder to mix elastomer components in multiple mixing zones at controlled temperatures. Elastomer and other ingredients are fed into the twin screw extruder continuously through precise loss-in-weight or volumetric feeders. The degradation temperature and/or cross linking temperature of the elastomer determines the rate at which the elastomer can be processed, since friction created during mixing heats the elastomer. Accordingly, the maximum rate of compounding is a function of the torque limit, cooling efficiency, and conveying capacity of the extruder. The conveying capacity and torque limit are also a function of the size of the extruder. The viscosity of the elastomer compound in the extruder, as measured by a Mooney viscosimeter (ASTM D1646), is typically in the range of about 20 to 250 units (ML(1+4)100C).

Abstract: An improvement in the method for extruding ethylene polymers which are extruded through an extruder apparatus including an extruder screw having a screw root and a series of flights having a leading edge and a trailing edge. The extruder apparatus also has an inlet end and a discharge end and wherein the pitch ratio divided by the depth ratio is greater than 2/3. The improvement provides a metallic coating selected from the group such as nickel coating or a matte chrome finish on the screw root and the leading and trailing edges of the flights, the coating being present in an amount sufficient to increase the output of the extruder screw.

Abstract: An extrusion device for processing thermoplastic plastics material and rubber has a housing and primary screw means rotatably mounted therein. The device includes a discharge zone in which a sleeve member provided with external flights is mounted on a bearing shaft so as to be rotatable about its longitudinal axis, which sleeve member is drivable by the primary screw means but in an opposite direction thereto so as to increase the discharge pressure acting on the material being processed.

Abstract: An apparatus for extracting a liquid from a workable mass of material includes a first screw section for transporting the material, a second screw section which applies a force on the material in a direction generally opposite that of the transport direction, and a second screw extruder at or near a liquid extraction location which provides a pinch point on the material. The pinch point substantially eliminates liquid flow countercurrent to the material transport direction.

Abstract: A pin transfer extruder is provided, wherein the pin-barrel and transfer mixing sections, which are known per se and have only been used individually hitherto, are jointly used in one extruder. Throttle pins, which are disposed in the transfer mixing section in the region of the greatest housing thread volume, permit universal use of the extruder in respect of the extruded material. The combination of both mixing systems permits the throughput of material to be increased in a surprising manner by 60% to 100%, while a constant mixing quality is maintained and the driving torque is halved. The number of the housing and screw flights remains independent of the cross-sectional area of the housing and screw threads because the number of housing and screw threads is constant.

Abstract: A pin transfer extruder is provided, wherein the pin-barrel and transfer mixing sections, which are known per se and have only been used individually hitherto, are jointly used in one extruder. Throttle pins, which are disposed in the transfer mixing section in the region of the greatest housing thread volume, permit universal use of the extruder in respect of the extruded material. The combination of both mixing systems permits the throughput of material to be increased in a surprising manner by 60% to 100%, while a constant mixing quality is maintained and the driving torque is halved.

Abstract: A resin extruder in which the degree-of-kneading of the resin can be effectively controlled. The invention can be applied to both a single-screw extruder and a twin-screw extruder. In either case, blocking walls are formed around a cylindrical portion of the screw or screws just upstream of the kneading section. A valve structure is provided in the walls to control the kneading of resin at the kneading section.

Abstract: A barrier screw having a feed zone, a compression zone and a metering zone, the screw including a shaft, a main flight provided on the shaft and a subflight provided on the shaft. The subflight is developed on the compression zone and then joins with a rear surface of the main flight prededing the subflight by one pitch at an end portion of the metering zone. The subflight defines a melt channel whsoe depth is substantially constant, so that the mixing function of the screw is improved.

Abstract: A single-screw degassing extruder for thermoplastic plastics materials and rubber is provided, wherein the pin-barrel and transfer sections, which are known per se and have only been used individually hitherto, are jointly used in one extruder. Throttle pins, which are disposed in the transfer section in the region of the greatest housing thread volume, permit universal use of the extruder in respect of the extruded material or combinations of extruded material and stripping agent, since the mixing efficiency of the extruder and the pressure of the extruded material upstream of a degassing opening in the extruder are thereby advantageously controllable.